Metrohm 765 Dosimat - Manual (Página 37)

4.1 General
765 Dosimat
33
4 Operation via RS232 Interface
4.1 General
The Dosimat offers an extensive remote control. Data transmission occurs via an interface
according to RS 232 C in half duplex procedure.
The syntax of the commands is based on the following principles:
• Commands are strings which always begin with a letter.
• Only the first three letters are significant, string length is unlimited.
• Actual parameters have to be separated by a space from the preceding command.
• The input range for numbers is -1E33 ... -1E-37, 0, 1E-37 ... 1E33.
Examples of possible numbers: 3.567
-.5
5.E4
-123.45E-12
• Set 'CR' + 'LF' at the end of a complete command.
'CR': carriage return (ASCII sign No. 13)
'LF': line feed (ASCII sign No. 10)
• All commands, where the Dosimat has to send data, begin with letter 'Q' (query).
• Each string sent by the Dosimat ends with 'CR' + 'LF'.
• Set handshake up for every character (asynchronous transfer).
There are several exceptions in order to avoid problems with time:
• The commands GO, STOP, FILL, CLEAR, and INFORMATION are so-called 1-byte
commands. They are simply transmitted as 'G', 'S', 'F', 'C', and 'I' . No separating and
terminating signs are necessary.
• With command 'I' (Information), the Dosimat sends two information bytes containing
the information READY, CODE, LOCK, LIMIT etc. see 4.2.7.
• Several commands can be transmitted "live", i.e. during a running function. All other
commands are recognized only if the Dosimat is in its ready state, see 4.2. If
commands are not recognized, the corresponding error bytes of information byte 2 are
set and may be inquired with command 'I'.